Computes the polynomial covariance function: $$k(s, t) = \sigma^2 (s \cdot t + c)^p$$
Details
The polynomial covariance function produces sample paths that are
polynomial functions of degree at most degree. Setting
degree = 1 and offset = 0 gives the linear kernel.
Examples
# Generate quadratic function samples
cov_func <- kernel.polynomial(degree = 2, offset = 1)
t <- seq(0, 1, length.out = 50)
fd <- make.gaussian.process(n = 10, t = t, cov = cov_func)
plot(fd)